Obesity is a condition of epidemic proportions in the United States. Recent government studies have indicated that up to 40% of Americans are obese and that, among those, almost 20% are morbidly obese. Obesity is not the problem in and of itself, but is the source of multiple pathological conditions, including cardiovascular disease, heart disease, stroke, diabetes, and obstructive sleep apnea. Recent studies have indicated that obesity can reduce a person's lifespan by an average of three years in adults and twenty years in children.
Many attempts have been made in the prior art to provide medications, devices, and surgical procedures for the treatment of obesity, all of which either have serious side effects or are basically ineffective. For example, various diets, supplements and pharmaceuticals have been developed and marketed, but none have shown any significant benefits to date in the treatment of obesity with the exception of some pharmaceuticals, which have unfortunately been found to cause a number of serious, life-threatening medical conditions. To date, there are no commercially available supplements or drugs that have been proven to be effective in promoting significant weight loss and at the same time that are free from serious collateral side effects.
Recognizing that no cure has been developed to date that is both effective and safe, the medical industry has introduced more extreme procedures, an example of which is the Roux-En-Y gastric bypass. This extensive and invasive surgery is highly effective but is also potentially lethal, with a 1-2% mortality rate, a six month recovery period, and a cost of tens of thousands of dollars, yet it is becoming increasingly popular because other available treatments do not produce the desired results. Gastric reduction, or simply removing a large segment of the stomach, is another procedure that is similar to gastric bypass and that, like gastric bypass, has also been associated with potentially lethal complications. Data from recent studies have indicated that even in the lowest risk groups, obesity surgery causes an average one-year mortality rate of nearly 5%.
In another attempt to treat obesity, devices have also been developed in the prior art that are aimed at providing a sense of fullness to a patient, so to cause the patient to reduce food intake. Such devices may be configured as stents that support the stomach or the pyloric valve to or that may be configured as permanent occluders. Unfortunately, these devices are implanted in the patient on an essentially permanent basis and typically include complex mechanical or electrical features that may stop working properly over time or that may require maintenance from time to time. Examples of such devices in the prior art can be found in U.S. Pat. Nos. 5,509,888; 6,067,991; 6,527,701; 6,689,046; 7,011,621; 7,037,344; 7,120,498; 7,122,058 and 7,167,750, and in U.S. patent Application Publications Nos. 2004/0172142; 2005/0273060; 2007/0016262; 2007/0027548; and 2007/0083224.
Evidence has been developed showing that benefits can be derived from reducing gastroduodenal flow. In unpublished, but recently presented data at the American Society for Bariatric Surgery conference of June 2003, stimulation of the gastric vagus nerve with subsequent reduction in gastric motility resulted in a loss of over 20% of excess weight over a nine month period. Furthermore, there is data suggesting that gastric vagotomy is also effective in the treatment of obesity through a similar mechanism. Unfortunately, these therapies require highly invasive, sometimes irreversible, surgical procedures, making them undesirable for a large segment of the obese population.